Andre Villas-Boas yesterday claimed Roman Abramovich "quit" on him when he was sacked by Chelsea in March. The 34-year-old is now back in the game as Tottenham Hotspur's new manager, the replacement for Harry Redknapp.

Villas-Boas knows he will have to work hard to dispel the idea he was a failure at Chelsea. He lasted less than nine months there, the victim of poor results and player power, and Chelsea went on to win the Champions League and the FA Cup without him. But he was adamant that Abramovich, the Chelsea owner, had acted dishonourably by discarding him so quickly.

"It is all very well that you cut the project short and Chelsea go on to win two trophies and then say how wonderful the squad was, but at the beginning nobody believed in that squad when we put it together," Villas-Boas said. "What I am saying is that I respect the decision of the owner of Chelsea but I will never accept it.

"I told him that for me it was him quitting on me when he had been so much involved in the beginning in bringing me in and he was the one who also was not putting up to the things he promised. For Chelsea to have won the Champions League and to have won the Cup was because we were still in those competitions."

Villas-Boas is not the first manager to be dismissed by Abramovich with little warning, with Jose Mourinho discarded in 2007 and Carlo Ancelotti fired despite having achieved a Premier League title and FA Cup Double in his first season. Avram Grant and Luiz Felipe Scolari, the latter a World Cup winner with Brazil, were also given short shrift.

Tottenham fans, understandably, will care little of the politics of Stamford Bridge. Their pressing concern centres upon whether a relatively inexperienced coach who never played at a high level can avoid repeating mistakes made at Chelsea. Villas-Boas believed that was the case.

"It was a tremendous learning experience, to be fair – you have to admit it," he said. "I am grateful to have gone through it because it makes me a better coach and a better person. I understand now certain things can be done better and, in the end, you evolve in different ways. Hopefully, I can apply the different things I have learnt."

Redknapp was dismissed last month despite having led Tottenham to fourth place last season, although Chelsea's Champions League triumph under Roberto Di Matteo meant that was worth only a place in next season's Europa League.

Top priority for Spurs is an assault on the Premier League title and Villas-Boas told his players exactly that within minutes of meeting them. Tottenham had shown signs last season that this was a possibility but Redknapp talked down their chances as often as he talked them up.

That was something Villas-Boas had certainly noticed. "It's very well to promote yourself to the title and to quit the week after. Not that this is a criticism but this is something, if we really want to go for it, this is something that we have to assume from the start. It's a proposition I have put to the players on the first day that we met. We have to see, of course, whether it's realistic or not.

"Other squads are evolving and you can't always compete with Chelsea and Manchester City for players. But we would like to assume this responsibility, not to put more pressure on ourselves but because it goes along with what we are trying to build."

Villas-Boas has made the signing of an experienced forward a priority but described negotiations to make Emmanuel Adebayor's loan move from City permanent as "just a remote possibility at the moment".

The former Spurs midfielder Steffen Freund was yesterday named as the club's new assistant head coach.